A clinch and a chafer are provided on the bead portion of a pneumatic tire to be in contact with the rim (i.e. in the chafing part). The rubber composition for producing a clinch or chafer is required to be excellent in the resistance to abrasion caused by contact with the rim (rim chafing resistance), the elongation at break, and the handling stability. Also, cars have been desired to achieve better fuel economy in recent years, which has led to a demand that a rubber composition for producing a clinch or chafer, as well as a rubber composition for producing a tread which accounts for a large portion of a tire, should achieve better fuel economy.
Patent Document 1 teaches a rubber composition for a clinch which is enabled to provide improved fuel economy and crack growth resistance by adjusting the amount of certain rubbers including tin-modified polybutadiene rubber in the rubber component and the amount of zinc oxide to respective values. Patent Document 2 teaches a rubber composition for a clinch which is enabled to have a lower volume resistivity value by blending silica, a silane coupling agent, and ketjen black in predetermined amounts relative to the amount of the rubber component including natural rubber. Notwithstanding there still remains room for improvement in improving the rim chafing resistance, elongation at break, handling stability, and fuel economy in a balanced manner.    Patent Document 1: JP 2008-24913 A    Patent Document 2: JP 2008-303295 A